Wednesday, 14 September 2016

Last of the Summertime 13th September 2016

We are currently experiencing an Indian Summer with temperatures reaching above 30 degrees Celsius and today was the hottest September day since 1911, bringing plenty of welcome sunshine to go with it.

Our driveway which we share with our neighbour has three small buddleias growing by a Cotswold Stone wall and as a consequence of being sheltered, undisturbed and secure these attract any number of butterflies, but of note during these last few warm sunny days have been the number of Small Tortoiseshell butterflies coming to imbibe of the honey smelling nectar from the cone shaped purple and white buddleia flowers. There have been up to a dozen at any one time along with the occasional Red Admiral and Comma.

This charming butterfly, once so common it was hardly given a second glance, is really quite beautiful when looked at closely and now, sadly has become yet another common species that has fallen on hard times and has become coveted as its comparative scarcity increases. The State of Nature report 2016, compiled by more than 50 conservation bodies and released tomorrow will state that one in ten UK wildlife species now face extinction due to the impact of intensive farming, urbanisation and climate change, with insects particularly badly affected. The UK is now 'among the most nature-depleted countries in the world', with most of the country having gone past the threshold at which 'ecosystems may no longer reliably meet society's needs'. Defra when asked to comment were as usual hopeless and provided a statement confirming all the positive things that have been achieved. I would expect nothing more from a body that is hostage to a self interested Tory Government and the bone headed National Farmers Union.

This year has been particularly bad for Small Tortoiseshells and their rapid decline in western Europe is still not fully understood. Periods of drought have a severe effect on them particularly in the early summer as the larvae need the nettle leaves on which they feed to be moist and wet which makes the leaves more nutritious and a lack of rain also inhibits the growth of the nettles. Other factors may also contribute to their decline such as environmental degradation, air pollution, parasites and contamination by pesticides and herbicides.

It is surely no coincidence that our garden and drive are pesticide and herbicide free and as long as I live here that is how it will remain, a zone of welcome to all insect life and it is one of the simple delights to walk down our drive in the early part of the morning when the tortoiseshells often descend to the ground to warm themselves on the flat stones of the driveway before flying up to feed on the buddleia. 

Walking down the drive at any time of day I am always welcomed by these bright little insects. flirting their wings and fluttering from flower to flower. There is  an innocent charm in their bright beauty and short lives as they go about their business heedless of the hustle and bustle of the road at the end of our drive. I usually stop to admire them as, like a living painting, they transport me for few minutes into their microcosm of the moment and all other worldly concerns are forgotten.

There is a sadness too in that they will soon be gone for this year, such perfection and beauty has no call on sentiment in the natural world, just in my human perception but nevertheless I am grateful for their presence that cheers me for each day they are here.

Although it is declining in Britain and western Europe it is a very widespread butterfly being found throughout temperate Europe and east to Asia, Siberia, China, Mongolia, Korea and Japan, wherever its food plant the Common Nettle grows. It has a long flying season extending from early spring to late autumn and adults hibernate over the following winter. Every year I find them secreted in the many secluded dark areas of our three hundred year old house or at the first sunny day of spring fluttering at the window having emerged from an unknown secret hiding place.

Their hibernation is a thing of wonder and they need to put on at least 20% of their body weight in order to hibernate successfully and survive the winter. They are very susceptible to predators in the first weeks of their hibernation and up to half can fall victim to predators in any given area. During hibernation they are able to supercool in order to keep from freezing and in sheltered areas they can stand up to -21 degrees Celsius without freezing.

When closed the bright orange upper sides of their wings are hidden and all one can see is an almost black underwing, looking leaf like as the butterfly holds its wings closed in the shape of a triangle.

If disturbed they will flick their wings open to suddenly reveal the bright colouring in an attempt to startle a predator and give it a vital few seconds to make its escape. The orange colouration also serves as a warning to birds that it is particularly unpalatable although there were one or two individuals today who showed distinct signs of attack from birds.

These butterflies also migrate, possessing an extra sensory organ in their antennae which enables them to detect air currents, position themselves in accordance with the air currents and then only commence migration at certain wind speeds. 

Did you also know that the Small Tortoiseshell is the national butterfly of Denmark?

1 comment:

  1. Thank you Ewan for drawing our attention to what should be a regular sight all over the country. The future for them,with the rape of the countryside ongoing, and indeed for all other 'common' species deserves as much,if not more, attention than the few success stories we hear about which seem to grab the headlines.